Can Fertilizer Really Change Into Rust?

Not many people think of the ingredients that are in a plant fertilizer. Most of us just care that the fertilizer is helping our plants remain healthy, happy, and flourishing. However, there are certain minerals and metals in fertilizers that can create issues. 

Fertilizer can really change into rust because fertilizers contain metals and minerals such as iron, magnesium, copper, and zinc. These ingredients can interact in your environment, turning to rust. 

In this article, I will discuss how fertilizer changes into rust and how gardeners can help avoid this from occurring in their own garden and lawn. 

Fertilizer Contains Metals and Minerals 

Every fertilizer is different, but all fertilizers tend to provide plants with the same additives and ingredients. Some of those ingredients are helpful minerals and metals. 

Both organic and synthetic fertilizers supply plants with the three main ingredients that they need to grow. These micronutrients are often known as the big three.

Here are the 3 most common ingredients supplied by fertilizers:

  • Nitrogen
  • Phosphorus
  • Potassium 

Many fertilizers, if not all, also contain micro and macronutrients to help certain plants thrive. Depending on the plant and the fertilizer, this can vary. But, it is most common to find other ingredients in your fertilizers: 

  • Zinc
  • Iron 
  • Sulfur
  • Calcium
  • Magnesium 
  • Boron 
  • Copper 
  • Manganese 

Sometimes, fertilizer is entirely absorbed by soil and fed to your plants. Other times, it takes a moment and does not always ingest. This can leave ingredients available on the surface of your soil or they can be pushed off onto concrete or other surfaces.

What Conditions Cause Fertilizer To Turn Into Rust?

It can seem odd to think that fertilizer might turn to rust, but it happens all the time. Most commonly, gardeners notice rust on the driveway or sidewalk near the gardens or lawns they are fertilizing. 

These conditions cause fertilizer to turn into rust: 

  1. Fertilizer is applied to your lawn or garden. 
  2. Fertilizer falls away from the soil and lands on a surface.
  3. Moisture interacts with your fertilizer. 
  4. The chemicals from your fertilizer create rust stains. 

Rust only tends to occur in the right environment. If you have fertilizer in a bag or on the top layer of your soil, you’re probably not going to experience rust. 

Things begin to rust when water or acidic materials come in contact with metals, and there is a corroding effect. Oxygen and moisture as well contribute to this.

Will Organic Fertilizers Rust? 

There are multiple variations of fertilizers on the market, and many preach that organic options are safer for your plants and your overall environment. Although that may be true, organic and synthetic fertilizers both contain similar ingredients. 

Organic fertilizers will rust because they contain micronutrients like magnesium, iron, and others. If you would like an organic fertilizer without metals and minerals, you can research a simple additive to use or make a homemade fertilizer for your plants. 

Unfortunately, there are not many fertilizers on the market that contain low amounts of minerals and metals. Organic options actually have high traces of minerals and metals because of the compounds that it includes. 

If you are looking for a fertilizer with low micronutrients, you might want to try finding a synthetic option or simple ingredients you can add to your plants. There are certain fertilizers that only contain the big three N-P-K or additives that only have one ingredient. This way, you can guarantee that there will not be any exposure to rust. 

However, finding simple additives is not as effective for your plant’s growth. Plants thrive with many nutrients in their fertilizer, and it is highly recommended to use a fertilizer that has micronutrients.

How To Prevent Fertilizer Rust

Unfortunately, rust does stain and it can be hard to remove from driveways and sidewalks.

To prevent rust from occurring, you can do the following: 

  • Hire a professional to fertilize for you carefully. 
  • Sweep your driveway and sidewalks after fertilizing. 
  • Be cautious when fertilizing, keeping away from any surfaces. 
  • If you do get fertilizer on the driveway, try your best to avoid having moisture come in contact with it.

Cleaning Fertilizer Rust

Rust is an unfortunate side-effect of using fertilizer, and many experience it often. While it can be prevented, you’re bound to experience fertilizer rust eventually if you’re an avid gardener or landscaper.

Luckily, there are many solutions to help you fix this issue.

The most common ingredient that causes rust stains is iron. Most fertilizers contain it, if not all. Because of this, many fertilizers are prone to rust, which can create tricky stains that are difficult to get rid of.

Fertilizer rust stains cannot be scrubbed away easily, so it’s best to skip that step if you were thinking of trying it. For most, it is a waste of time, energy, and supplies.

The best way to clean rust from fertilizer is to find a rust remover. Many like to use organic options since the rust is close to their lawn or garden, but if organic rust remover isn’t a priority for you, I suggest investing in Singerman’s Laboratories Rust Remover (available on

This remover is especially helpful for concrete, sidewalks, and even stone surfaces. It doesn’t cause harm to your plants, but it’s still advisable to exercise caution when handling gardening chemicals.

Natural Fertilizer Rust Solutions 

Most rust removers are not incredibly harmful to your plants or to your lawn. They accomplish the removal process easily, and are great options for people who don’t have organic home gardens.

However, they aren’t the best solution for the fertilizer rust issue if organic gardening is a priority for you. This is because many rust removers have chemicals that can be harmful to the health of you, your pets, and your plants.

If a natural solution to fertilizer rust is important to you, there are quite a few options you can use. My favorite solution involves using vinegar to solve the problem.

Vinegar is an excellent substance to have in stock. It works for all sorts of household functions, and many people use it as a natural all-purpose cleaner. It’s great for killing bacteria and making things clean. Fortunately, it’s also an excellent option for fertilizer rust removal.

If you’re interested in using vinegar to rid your garden or lawn of fertilizer rust, it’s important to dilute the vinegar with water. This option is best for light rust stains that you catch in time before they have set on your driveway or sidewalk.

With vinegar, you may need to scrub the surface you’re treating multiple times to see results. If you do not see results after a while, a stronger acid might be recommended. 

A common one that works well is hydrochloric acid. It is commonly used for pools. To some, this might not be viewed as all-natural, but it may be better than using a rust remover that has multiple toxic ingredients.

Does Soda Get Rid of Fertilizer Rust? 

Soda does get rid of fertilizer rust. Surprisingly, soda is an excellent solution to this problem because it’s acidic. The best brand to use for fertilizer rust removal is Coca-Cola, which will provide the quickest results. 

Here’s how to use soda to get rid of fertilizer rust:

  1. The first step is to pour Coca-Cola all over your rusted-surface.
  2. If not in the sun, you can leave the coca-cola there to soak in the rust for a little while. It’s best to avoid this step if your surface is in the sun, because Coca-cola will dry and stain.
  3. Rinse the soda from the rusted surface.

Another option is to leave the Coca-Cola on the rusted surface overnight. 

If soaking your surface is not possible or it’s warm where you live, individuals can scrub the surface instead. A rough material works great for a sponge to scrub, and you can keep scrubbing for as long as you need to.

Once it is finished, you can wipe up the Coca-Cola and it should have better results than beforehand.

Why Is Fertilizer So Corrosive? 

If you have experienced fertilizer rust, you probably know what a pain it is. It can ruin your driveway, fences, and sidewalks, and it is hard to treat. This is because it is a corrosive product. 

Fertilizer is so corrosive because it absorbs moisture from the air and other acidic substances that help dissolve it. In the process of dissolving, it can cause corrosion when it is on a surface such as metal, wood, or cement. 

The main reason that one may say that fertilizer is corrosive is because it absorbs water and moisture. Fertilizer is designed to absorb moisture and works relatively well with it when it is feeding plants and soil. But, this becomes a much greater issue when soil is not the surface. 

Fertilizer can cause rust even if water is not present. If fertilizer is on a metal surface, individuals can expect that some form of rust may occur. 

The good thing is that many fertilizers are not in contact with rust, cement, and wood as often as one would think. And, it may not be that significant of an issue in the long run. 

Final Thoughts

Fertilizer is an essential part of gardening. However, using fertilizer can make your lawns and gardens prone to rust due to the amount of metals and minerals included in the product. While these ingredients are nutritious to the plants, they can be a pain when rust occurs.

Fortunately, there are ways to solve this issue. By following the tips this article provides, you can keep your garden healthy and clean for a long time to come.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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